1. Field of the Invention
The present invention relates to color management, and more particularly, to a color management circuit and a related color management method. The color calibration method and system provided by the embodiments of the present invention enable a color management circuit to be accurately configured, thereby significantly improving the matching between a display device and a color space.
2. Description of the Prior Art
In order to have a consistent displaying effect when displaying same colors on different display devices, there are several industrial color space standards for image storing and display devices, including well-known standards RGB (sRGB) and Adobe RGB.
sRGB color space is usually used in monitors, printers, and the Internet. When colors in an image data are defined in sRGB color space, the image can be perfectly displayed on a display device that is fully matched with sRGB color space. However, a color gamut of a general display device is usually not fully matched with the color gamut defined in sRGB space. Please refer to FIG. 1 which exhibits relationships between the color gamut of the sRGB color space and color gamuts of different display devices on a CIE1931 xy chromaticity diagram. As shown in FIG. 1, colors regarding the area inside the triangle K represent the color gamut defined in sRGB color space while colors regarding the areas inside the triangle L and M respectively represent the color gamuts supported by different display devices. In general, when the color gamut of the display device is not fully matched with the color gamut defined in sRGB color space, a color management circuit or software is required to make the display device able to display colors that are not originally supported by the display device, in order to approach the corresponding colors as defined in sRGB color space.
It is necessary to calibrate the display device according to different color spaces. With the help of the color management circuit, the display device is able to accurately display colors defined in different color spaces (e.g. sRGB or Adobe RGB). In a conventional color calibration process, the colors of white, red, green, blue, cyan, magenta, and yellow having the maximum luminance that can be displayed by the display device are utilized as a reference to adjust the proportion of RGB components of the display device in order to make these seven colors approach the corresponding colors having the maximum luminance as defined in the color space.
For sRGB color space, however, the conventional color calibration process does not deal with the color conversion between nonlinear and linear characteristics as defined in sRGB color space. As a result, other colors excluding the colors having the maximum luminance are not properly calibrated so that the display device can not display these other colors to a high degree of accuracy. In addition, the conventional technology of calibrating the display device on production lines is detailed and complicated, and requires manpower for repeated measurement and adjustments. Therefore, it is impossible for the conventional technology to calibrate and adjust all the display devices on a production line individually; instead, the conventional technology measures and adjusts several samples on the production line, then utilizes parameters obtained from the samples to calibrate all the display devices. There will inevitably be fabrication deviations (e.g. parameter drift of the panel) between different display devices on the same production line. The conventional technology cannot provide the most proper parameters for each display device, and thereby fails to derive the best color calibration result.
As can be seen from the above-mentioned points, the conventional technology still has many shortcomings.